Fungalpedia – Note 3299, Archaeorhizomycetes
Archaeorhizomycetes Rosling & T.Y. James, Science, N.Y. 333(no. 876): 879 (2011).
Citation when using this data: Wijayawardene NN et al. 2024 – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank.
Classification: Taphrinomycotina, Ascomycota, Dikarya, Fungi.
Archaeorhizomycetes is globally distributed, i.e., sequences taxonomically assigned to the class have been detected in 18% of all samples currently contained in the globalfungi.com database and include records from all continents (Větrovský et al. 2020) and sequences of Archaeorhizomycetes are frequently observed in environmental soil and root samples (Schadt et al. 2003; Porter et al. 2008; Rosling et al. 2011, 2013). Based on sequence similarity and clustering of published eDNA amplicon sequences, the class has been estimated to comprise at least 500 species (Menkis et al. 2014). However, estimating species richness from eDNA metabarcoding data is not trivial and global richness estimates based on clustering at 98.5% of environmental sequences available as Short Read Archive data has suggested that Archaeorhizomycetes may encompass as many as 16,231 taxa (Hawksworth and Lücking 2017). The authors emphasise that the latter number is likely inflated by a combination of sequencing errors and artifacts of the clustering method. More moderate estimates include the gbif.org database, which currently includes 17,131 occurrences and 767 species hypotheses for Archaeorhizomycetes. The curated fungal sequence database UNITE (version 9.0, Nilsson et al. 2018) currently has 765 species hypotheses classified in the class Archaeorhizomycetes, based on its 1.5% sequence dissimilarity threshold. Of these, 126 are also recovered in the globalfungi.com database, which currently includes fungal eDNA amplicon data from 515 studies (Větrovský et al. 2020). Local species richness can be high, with records of 278 Archaeorhizomyces hypothesised species in an alpine habitat (Pinto-Figueroa et al. 2019), 80 species recovered in a subtropical evergreen shrub bog (Tian et al. 2021) and 68 hypothesised species detected in a Swedish boreal forest site (Kalsoom Khan et al. 2020). Irrespective of the actual species richness, the two species that have been cultured, formally described, and named, Archaeorhizomyces borealis Menkis et al. and Archaeorhizomyces finlayi Rosling & T. James, certainly represent only a fraction of the true diversity in the class. Despite repeated efforts, no additional species have been successfully captured in pure culture, but two additional species, A. secundus and A. victor, have been proposed based on phylogenetic and ecological evidence from eDNA amplicon data (Kalsoom Khan et al. 2020).
Type order: Archaeorhizomycetales Rosling & T.Y. James, Science, N.Y. 333(no. 876): 879 (2011).
Type family: Archaeorhizomycetaceae Rosling & T.Y. James, Science, N.Y. 333(no. 876): 879 (2011).
Type genus: Archaeorhizomyces Rosling & T.Y. James, Science, N.Y. 333(no. 876): 879 (2011).
Type species: Archaeorhizomyces finlayi Rosling & T.Y. James, Science, N.Y. 333(no. 876): 879 (2011).
Other accepted species: Species Fungorum – search Archaeorhizomycetes.
References
Entry by
Nalin N. Wijayawardene, Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing, Yunnan 655011, P.R. China, Tropical Microbiology Research Foundation, 96/N/10, Meemanagoda Road, 10230 Pannipitiya, Sri Lanka, Department of Bioprocess Technology, Faculty of Technology, Rajarata University, Sri Lanka
Published online 25 September 2026